Apparatus and method for manufacturing three-dimensional netted structure

ABSTRACT

A method of manufacturing a three-dimensional netted structure by (a) extruding molten filaments of a thermoplastic resin downward from a die via a mouthpiece of the die having a plurality of holes such that the filaments drop under the force of gravity in between drawing-down units, (b) drawing down the assembly of extruded filaments at a speed lower than the filament dropping speed by the drawing-down units, and (c) cooling the resultant filaments with a liquid. The drawing-down units are submerged or partly-submerged in a liquid. The distance between the drawing-down units is smaller than the width of an assembly of the extruded filaments. Four surfaces of the assembly of the filaments are contacting the drawing-down units before or after the drawing-down units are submerged.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 12/497,567, filed Jul. 3, 2009, now pending, which is acontinuation-in-part of U.S. patent application Ser. No. 10/221,568,having a 371(c) date of Sep. 13, 2002, issued as U.S. Pat. No. 7,625,629on Dec. 1, 2009, which is a National Stage Appl. filed under 35 USC 371of Int'l Pat. Appl. No. PCT/JP2001/002046, filed on Mar. 15, 2001, andclaims foreign priority benefits to Japanese Pat. Appl. Nos. 2000-072977filed Mar. 15, 2000, 2000-279721 filed Sep. 14, 2000, 2000-279792 filedSep. 14, 2000, 2000-281309 filed Sep. 18, 2000, 2000-281319 filed Sep.18, 2000, 2000-281329 filed Sep. 18, 2000, 2000-281341 filed Sep. 18,2000, and 2000-285855 filed Sep. 20, 2000. The contents of all of theseapplications, including any intervening amendments thereto, areincorporated herein by reference in their entirety. Inquiries from thepublic to applicants or assignees concerning this document or therelated applications should be directed to: Matthias Scholl P. C.,Attn.: Dr. Matthias Scholl Esq., 14781 Memorial Drive, Suite 1319,Houston, Tex. 77079.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a three-dimensional netted structure used fora cushioning material and the like, and a method of and an apparatus formanufacturing the same.

2. Brief Description of the Related Arts

Known methods of manufacturing a void-carrying three-dimensional nettedstructure include a method disclosed in Japanese Patent PublicationKOKOKU No. S50-39185, or a method disclosed in Japanese Patent Laid-OpenKOKAI No. S60-11352, etc., which is adapted to manufacture resin cottonon which polyester fibers are bonded with a bonding agent made of, forexample, a rubber-based material. There are also methods of orapparatuses for manufacturing a void-carrying three-dimensional nettedstructure by entangling resin threads by endless belts, and such methodsor apparatuses include the invention disclosed in Japanese PatentLaid-Open KOKAI No. H11-241264, etc.

However, the demands for a product of such a three-dimensional nettedstructure have been diversified. It is necessary that each of nettedstructures manufactured be finished to one of different shapes bycutting or molding the netted structures to demanded shapes in a laterstage of the manufacturing stage. This causes a product finishingoperation to become very complicated.

A three-dimensional netted structure manufactured by a prior art methodbecomes low in density in some cases. Since both surface portions of abundle contact belt conveyors, outer surfaces of the bundle aresubstantially flattened. However, left and right end surfaces of thebundle have an irregular, helical shape, and side surfaces thereof havea laterally wavy non-straight shape.

The endless belts mentioned above by which a resin threads are entangledis liable to be damaged due to the heat, etc., so that there is a fearof encountering a problem concerning the durability of the endlessbelts.

Therefore, the invention provides a method of and an apparatus formanufacturing a three-dimensional netted structure, capable of renderingit unnecessary to carry out a finishing operation in a later stage,improving the degree of straightness of the side surfaces of the nettedstructure, meeting a demand for finishing the netted structure tomodified shapes, and improving the durability of the netted structure.

SUMMARY OF THE INVENTION

In view of these various problems, in certain embodiments, the inventionis directed to a three-dimensional netted structure manufactured bypreparing a thermoplastic resin as a raw material or a main rawmaterial; forming the resin into a plurality of helically and randomlyentangled, partly and thermally bonded filaments by extrusion molding;and cooling the resultant filaments with water so as to obtain a nettedstructure having sparse and dense portions arranged alternately in thematerial extruding direction. This enables the netted structure to beapplied to a cushioning material and the like which is made possible tobe hung at a sparse portion thereof on a hook.

In particular, provided is a three-dimensional netted structure having anetted structure being manufactured by preparing a thermoplastic resinas a raw material or a main raw material, wherein the resin is formedinto a plurality of helically and randomly entangled, partly andthermally bonded filaments by extrusion molding; and the resultantfilaments are cooled with a liquid so as to obtain a netted structurehaving hollow portions arranged continuously in the material extrudingdirection, the structure is a three-dimensional plate type nettedstructure that the apparent density is 0.02 to 0.9 g/cm³, havingregenerated members inserted in the hollow portions.

In particular, provides is a three-dimensional netted structurecomprising: a netted structure being manufactured by preparing athermoplastic resin as a raw material or a main raw material; and aplurality of hollow portions which are spaced apart and formed in thenetted structure, wherein the hollow portions extend within the nettedstructure from one end to another end of the netted structure, whereinthe resin is formed into a plurality of helically and randomlyentangled, partly and thermally bonded filaments by extrusion molding,wherein the filaments are cooled with a liquid so as to obtain the anetted structure having the hollow portions arranged continuously in amaterial extruding direction, and wherein the netted structure is athree-dimensional plate type netted structure having an apparent densityof 0.02 to 0.9 g/cm³.

In other embodiments, the invention is directed to a three-dimensionalnetted structure manufactured by preparing a thermoplastic resin as araw material or a main raw material; forming the resin into a pluralityof helically and randomly entangled, partly and thermally bondedfilaments by extrusion molding; and cooling the resultant filaments witha liquid so as to obtain a netted structure having hollow portionsarranged in the material extruding direction. This enables the hollowportions to be utilized effectively by inserting other members thereinor by using the hollow portions in a different manner, and the nettedstructure to be thereby applied to various uses.

In particular provided is a three-dimensional netted structure having anetted structure being manufactured by preparing a thermoplastic resinas a raw material or a main raw material, wherein the resin is formedinto a plurality of helically and randomly entangled, partly andthermally bonded filaments by extrusion molding; and the resultantfilaments are cooled with a liquid so as to obtain a sheet having apercentage of void of zero continuously in the material extrudingdirection, forming the sheet into wavy shape in the material extrudingdirection, the structure is a three-dimensional plate type nettedstructure that the apparent density is 0.02 to 0.9 g/cm³.

In particular provided is a three-dimensional netted structurecomprising: a netted structure being manufactured by preparing athermoplastic resin as a raw material or a main raw material; and asheet which is included in an internal portion of the netted structure,wherein the sheet is formed in a wavy pattern and extends from one endto another end of the netted structure, wherein the resin is formed intoa plurality of helically and randomly entangled, partly and thermallybonded filaments by extrusion molding, wherein the resultant filamentsare cooled with a liquid so as to obtain a netted structure whichincludes the sheet having a percentage of void of zero continuously in amaterial extruding direction, thereby forming the sheet into the wavypattern in the netted structure in the material extruding direction, andwherein the netted structure is a three-dimensional plate type nettedstructure having an apparent density of 0.02 to 0.9 g/cm³.

In other embodiments, the invention is described to a three-dimensionalnetted structure manufactured by preparing a thermoplastic resin as araw material or a main raw material; forming the resin into a pluralityof helically and randomly entangled, partly and thermally bondedfilaments by extrusion molding; and cooling the resultant filaments witha liquid so as to obtain a sheet having a percentage of void ofsubstantially zero in the material extruding direction. This enables thesoundproofing and shock absorbing performance of the sheet to beimproved.

In other embodiments, the invention is directed to a three-dimensionalnetted structure manufactured by preparing a thermoplastic resin as araw material or a main raw material; forming the resin into a pluralityof helically and randomly entangled, partly and thermally bondedfilaments by extrusion molding; and cooling the resultant filaments witha liquid so as to obtain a netted structure having not smaller than twoseparable regions. This enables the difficulty, which was encountered ina related art netted structure of this kind, in recycling a complexresin and the like to be overcome by providing the netted structure withnot smaller than two separable regions.

In other embodiments, the invention is directed to a three-dimensionalnetted structure manufactured by preparing a thermoplastic resin as araw material or a main raw material; forming the resin into a pluralityof helically and randomly entangled, partly and thermally bondedfilaments by extrusion molding; and cooling the resultant filaments witha liquid so as to obtain an insulating material or a sound absorbingmaterial. This enables the netted structure to be used as a buildingmaterial, an interior finishing material for automobiles, and materialsfor similar purposes.

In other embodiments, the invention is directed to a three-dimensionalnetted structure manufactured by preparing a thermoplastic resin as araw material or a main raw material; forming the resin into a pluralityof helically and randomly entangled, partly and thermally bondedfilaments by extrusion molding; cooling the resultant filaments with aliquid; and applying a fire-resistant material to the cooled filamentsor enclosing the cooled filaments with the same material or adding thesame material to the cooled filaments. This enables the reliability ofan interior heat insulating material, an exterior heat insulatingmaterial, an interior finishing material for a side wall and an interiorfinishing material for automobiles to be improved.

In other embodiments, the invention is directed to a three-dimensionalnetted structure manufactured by preparing a thermoplastic resin as araw material or a main raw material; forming the resin into a pluralityof helically and randomly entangled, party and thermally bondedfilaments by extrusion molding; and cooling the resultant filaments witha liquid so as to obtain a seedbed for planting trees on a roof. Thisenables the recycling of the seedbed to be done, and the planting oftrees on a roof to be promoted.

In other embodiments, the invention is directed to a three-dimensionalnetted structure manufactured by preparing a thermoplastic resin as araw material or a main raw material; forming the resin into a pluralityof helically and randomly entangled, partly and thermally bondedfilaments by extrusion molding; and cooling the resultant filaments witha liquid so as to obtain a gardening cushioning material. This enablesthe netted structure to be used instead of a wooden trellis, and thedurability thereof to be improved.

In other embodiments, the invention is directed to a three-dimensionalnetted structure manufactured by preparing a thermoplastic resin as araw material or a main raw material; forming the resin into a pluralityof helically and randomly entangled, partly and thermally bondedfilaments by extrusion molding; and cooling the resultant filaments witha liquid so as to obtain a netted structure having polyhedral ormiscellaneously shaped side surfaces.

In other embodiments, the invention is directed to a three-dimensionalnetted structure manufactured by preparing a regenerated thermoplasticresin, especially, polyethylene terephthalate as a raw material or amain raw material; forming the resin into a plurality of helically andrandomly entangled, partly and thermally bonded filaments by extrusionmolding; and cooling the resultant filaments with a liquid so as toobtain a recycled netted structure. This enables the recovery ofpolyethylene terephthalate bottles, etc. to be promoted.

In other embodiments, the invention is directed to a three-dimensionalnetted structure manufactured by preparing a brittleness-causing rawmaterial-containing thermoplastic resin as a raw material or a main rawmaterial; forming the resin into a plurality of helically and randomlyentangled, partly and thermally bonded filaments by extrusion molding,and cooling the resultant filaments with a liquid so as to obtain anetted structure capable of being brittle fractured by applying anexternal force thereto. This enables a shock occurring due to thecollision of a vehicle to break the texture of the three-dimensionalnetted structure, so that damage to a vehicle due to the collisionthereof can be prevented.

In particular, provided is a three-dimensional netted structure having anetted structure being manufactured by preparing thermoplastic resin asa raw material or a main raw material containing a theness-causing rawmaterial; wherein the resin is formed into a plurality of helically andrandomly entangled, partly and thermally bonded filaments by extrusionmolding; and the resultant filaments are cooled with a liquid so as toobtain a netted structure capable of the fractured by applying anexternal force thereto after cooling and hardening.

In particular, provided is a three-dimensional netted structurecomprising: a netted structure being manufactured by preparingthermoplastic resin as a raw material or a main raw material containinga brittleness-causing raw material, wherein the resin is formed into aplurality of helically and randomly entangled, partly and thermallybonded filaments by extrusion molding, wherein the filaments areextruded along a plane in a single direction to form the nettedstructure, wherein the filaments upon being extruded are cooled with aliquid so as to obtain a netted structure having hardened filaments, andwherein the netted structure is brittle and can be fractured by applyingan external force of a predetermined amount thereto.

In other embodiments, the invention is directed to a three-dimensionalnetted structure comprising: a netted structure being manufactured bypreparing a thermoplastic resin as a raw material or a main rawmaterial, wherein the netted structure includes an inner region having apredetermined apparent density and an outer peripheral region adjacentthe inner region having an apparent density higher than thepredetermined apparent density, wherein the resin is formed into aplurality of helically and randomly entangled, partly and thermallybonded filaments by extrusion molding, wherein the filaments are cooledwith a liquid so as to obtain the netted structure having the innerregion and the outer peripheral region arranged continuously in amaterial extruding direction, and wherein the netted structure is athree-dimensional plate type netted structure having the predeterminedapparent density and the apparent density greater than the predeterminedapparent density of 0.02 to 0.9 g/cm³.

In other embodiments, the invention is directed to a three-dimensionalnetted structure formed out of a thermoplastic resin as a raw materialor a main raw material by extrusion molding, in which a plurality offilaments are helically and randomly entangled and thermally bondedtogether and the resultant filaments are cooled with a liquid so as toobtain the netted structure having upper and lower surfaces, two sidesurfaces and left and right end surfaces; characterized in that thestructure is four-surface molded wherein the upper and lower surfacesand the two side surfaces are molded.

In a class of this embodiment, the structure additionally comprises asubstantially non-void-carrying sheet, which forms a wavy shape in thematerial extruding direction.

In a class of this embodiment, the apparent density of the nettedstructure is 0.02 to 0.9 g/cm³.

In a class of this embodiment, the netted structure has sparse and denseportions arranged alternately in the material extruding direction.

In a class of this embodiment, the netted structure has a single or aplurality of beam-like high-density regions arranged in the direction ofthe thickness of the netted structure.

In other embodiments, the invention is directed to an apparatus formanufacturing a three-dimensional netted structure which is obtained byextruding molten filaments of a thermoplastic resin, a raw material or amain raw material downward from a die having a plurality of holes;having the filaments drop naturally between partly-submergeddrawing-down units; when a three-dimensional netted structure ismanufactured by drawing the filaments between the drawing-down units ata speed lower than a filament dropping speed, a distance between thedrawing-down units being set smaller than a width of an assembly of theextruded filaments, the drawing-down units being arranged so that atleast three or four surfaces of the assembly of the filaments contactthe drawing-down units before or after the drawing-down units aresubmerged. This renders it unnecessary to carry out a finishingoperation in a later stage, and enables the degree of straightness ofthe side surfaces of the netted structure to be heightened.

In particular provided is an apparatus for manufacturing athree-dimensional netted structure having a netted structure beingobtained by extruding molten filaments of a thermoplastic resin as a rawmaterial or a main raw material, comprising: a die having a plurality ofholes, the filaments being downward from the die; and drawing-down unitspartly-submerged in water, having the filaments drop naturally inbetween; wherein the drawing-down units draw the filaments in between ata speed lower than a filament dropping speed, a distance between thedrawing-down units being set smaller than a width of an assembly of theextruded filaments, and the drawing-down units are arranged so that foursurfaces of the assembly of the filaments contact the drawing-down unitsbefore or after the drawing-down units being submerged, driving systemsof the opposite drawing-down units are formed by fixing.

In other embodiments, the invention is directed to an apparatus formanufacturing a three-dimensional netted structure which is obtained byextruding molten filaments of a thermoplastic resin, a raw material or amain raw material downward from a die having a plurality of holes;having the filaments drop naturally between partly-submerged rollers;and drawing the filaments between the rollers at a speed lower than afilament dropping speed, a distance between the rollers being setsmaller than a width of an assembly of the extruded filaments, at leastone surface of the assembly of the filaments contacting the rollersbefore or after the rollers are submerged. This enables the simplicityof the apparatus and the easiness of designing the apparatus to beattained.

In other embodiments, the invention is directed to an apparatus formanufacturing a three-dimensional netted structure which is obtained byextruding molten filaments of a thermoplastic resin, a raw material or amain raw material downward from a die having a plurality of holes;having the filaments drop naturally between partly-submerged, slidablesurface-carrying plate members a distance between which is set so as todecrease gradually in the downward direction; and drawing the resultantfilaments between the plate members at a speed lower than a filamentdropping speed, a distance between lower portions of the plate membersbeing set smaller than a width of an assembly of the extruded filaments,at least one surface of the assembly of the filaments contacting theplate members before or after the plate members are submerged. Thisenables the miniaturization of the apparatus to be attained by reducingor omitting movable parts.

In other embodiments, the invention is directed to an apparatus formanufacturing a three-dimensional netted structure which is obtained byextruding molten filaments of a thermoplastic resin, a raw material or amain raw material downward from a die having a plurality of holes;having the filaments drop naturally between partly submergeddrawing-down units; and drawing the filaments between the drawing-downunits at a speed lower than a filament dropping speed, a distancebetween the drawing-down units being set smaller than a width of anassembly of the extruded filaments, at least one surface of the assemblyof the filaments contacting the drawing-down units before or after thedrawing-down units are submerged, a cross section of outercircumferential members of the drawing-down units being set to modifiedshapes. This enables an operation in a later stage to be omitted.

In other embodiments, the invention is directed to an apparatus formanufacturing a three-dimensional netted structure which is obtained byextruding molten filaments of a thermoplastic resin, a raw material or amain raw material downward from a die having a plurality of holes;having the filaments drop naturally between partly-submergeddrawing-down units; and drawing the filaments between the drawing-downunits at a speed lower than a filament dropping speed, a distancebetween the drawing-down units being set smaller than a width of anassembly of the extruded filaments, at least one surface of the assemblyof the filaments contacting the drawing-down units before or after thedrawing-down units are submerged, the die being provided with a complexdie which has not smaller than two chambers and a plural-hole-carryingmouthpiece, the molten filaments of a thermoplastic resin, a rawmaterial or a main raw material being extruded downward from the holesof the mouthpiece via different passages isolated from one another bypartitions. This enables a separable three-dimensional netted structureto be manufactured.

In other embodiments, the invention is directed to an apparatus formanufacturing a three-dimensional netted structure which is obtained byextruding molten filaments of a thermoplastic resin, a raw material or amain raw material downward from a die having a plurality of holes;having the filaments drop naturally between partly-submergeddrawing-down units; and drawing the resultant filaments between thedrawing-down units at a speed lower than a filament dropping speed, adistance between the drawing-down units being set smaller than a widthof an assembly of the extruded filaments, at least one surface of theassembly of the filaments contacting the drawing-down units before orafter the drawing-down units are submerged, the drawing-down units beingprovided with circumferentially moving members, which are provided atcircumferences thereof with circumferentially extending metal nets orplate members. This enables the durability of the drawing-down units tobe improved.

In other embodiments, the invention is directed to an apparatus formanufacturing a three-dimensional netted structure which is obtained byextruding molten filaments of a thermoplastic resin, a raw material or amain raw material downward from a die having a plurality of holes;having the filaments drop naturally between partly-submergeddrawing-down units; and drawing the filaments between the drawing-downunits at a speed lower than a filament dropping speed, a distancebetween the drawing-down units being set smaller than a width of anassembly of the extruded filaments, at least one surface of the assemblyof the filaments contacting the drawing-down units before or after thedrawing-down units are submerged, regions of a high density of holes andregions of a low density of holes being formed on a mouthpiece of thedie. This enables the range of designing of the apparatus to be widened.

In other embodiments, the invention is directed to an apparatus formanufacturing a three-dimensional netted structure having a nettedstructure being obtained by extruding molten filaments of athermoplastic resin as a raw material or a main raw material,comprising: a die having a plurality of holes, the filaments beingdownward from the die; and drawing-down units partly submerged in water,having the filaments drop naturally in between; and wherein thedrawing-down units draw the filaments in between at a speed lower than afilament dropping speed, a distance between the drawing-down units isset smaller than a width of an assembly of the extruded filaments, atleast one surface of the assembly of the filaments contact thedrawing-down units before or after the drawing-down units beingsubmerged, forming a slit in a suitable portion of a mouthpiece.

In other embodiments, the invention is directed to an apparatus formanufacturing a three-dimensional netted structure having a nettedstructure being obtained by extruding molten filaments of thermoplasticresin as a raw material or a main raw material containing a thenesscausing raw material, comprising: a die having a plurality of holes, thefilaments being downward from the die; and drawing-down unitspartly-submerged in water, having the filaments drop naturally inbetween; wherein the drawing-down units draw the filaments in between ata speed lower than a filament dropping speed, a distance between thedrawing-down units being set smaller than a width of an assembly of theextruded filaments, and the drawing-down units are arranged so that atleast one surface of the assembly of the filaments contact thedrawing-down units before or after the drawing-down units beingsubmerged, the netted structure capable of the fractured by applying anexternal force thereto.

In other embodiments, the invention is directed to an apparatus formanufacturing a three-dimensional netted structure, as described herein,having a netted structure being obtained by extruding molten filamentsof a thermoplastic resin as a raw material or a main raw material,comprising: a die having a plurality of holes, the filaments beingdownward from the die; and drawing-down units partly-submerged in water,having the filaments drop naturally in between, wherein the drawing-downunits draw the filaments in between at a speed lower than a filamentdropping speed, a distance between the drawing-down units being setsmaller than a width of an assembly of the extruded filaments, whereinthe drawing-down units are arranged so that four surfaces of theassembly of the filaments contact the drawing-down units before or afterthe drawing-down units being submerged, wherein a curved plate extendsbetween the die and the draw-down unit thereby introducing the filamentsto the draw-down unit, and wherein the curved plate is given at theirouter surfaces having a slidability, the curved plate is arranged sothat a distance inbetween decreases from upper portions thereof towardlower portions thereof.

In other embodiments, the invention is directed to an apparatus formanufacturing a three-dimensional netted structure having a nettedstructure being obtained by extruding molten filaments of athermoplastic resin as a raw material or a main raw material, theapparatus comprising: a die, a mouthpiece of the die having a pluralityof holes, the filaments being extruded downward from the die via themouthpiece; and drawing-down units partly-submerged in liquid, havingthe filaments drop in between; wherein the drawing-down units draw thefilaments in between at a speed lower than the filament dropping speed,and the distance between the drawing-down units is set smaller than thewidth of the assembly of the extruded filaments, and wherein thedrawing-down units are arranged so that four surfaces of the assembly ofthe filaments contact the drawing-down units before or after thedrawing-down units are submerged.

In a class of this embodiment, the mouthpiece has a slit in addition tothe plurality of holes, the slit extending in the lengthwise directionof the mouthpiece, whereby the three dimensional netted structureadditionally comprises a substantially non-void-carrying sheet, thenon-void-carrying sheet forming a wavy shape in the material extrudingdirection.

In another class of this embodiment, the mouthpiece has a region notprovided with holes so as to make a hollow portion in thethree-dimensional netted structure arranged in the material extrudingdirection.

In other embodiments, the invention is directed to an apparatus formanufacturing a three-dimensional netted structure, the netted structurecomprising: a netted structure being manufactured by preparing athermoplastic resin as a raw material or a main raw material; and asheet which is included in an internal portion of the netted structure,wherein the sheet is formed in a wavy pattern and extends from one endto another end of the netted structure, wherein the resin is formed intoa plurality of helically and randomly entangled, partly and thermallybonded filaments by extrusion molding, wherein the filaments are cooledwith a liquid so as to obtain the netted structure which includes thesheet having a percentage of void of zero continuously in a materialextruding direction, thereby forming the sheet into the wavy pattern inthe netted structure in the material extruding direction, and whereinthe netted structure is a three-dimensional plate type netted structurehaving an apparent density of 0.02 to 0.9 g/cm³; the apparatuscomprising: a die, a mouthpiece of the die having a plurality of holes,the filaments being extruded downward from the die via the mouthpiece;and drawing-down units partly-submerged in liquid, having the filamentsdrop in between; wherein the drawing-down units draw the filaments inbetween at a speed lower than the filament dropping speed, and thedistance between the drawing-down units is set smaller than the width ofthe assembly of the extruded filaments, and wherein the drawing-downunits are arranged so that four surfaces of the assembly of thefilaments contact the drawing-down units before or after thedrawing-down units are submerged.

In a class of this embodiment, the mouthpiece has a slit in addition tothe plurality of holes, the slit extending in the lengthwise directionof the mouthpiece, whereby the three dimensional netted structureadditionally comprises a substantially non-void-carrying sheet, thenon-void-carrying sheet forming a wavy shape in the material extrudingdirection.

In another class of this embodiment, the mouthpiece has a region notprovided with holes so as to make a hollow portion in thethree-dimensional netted structure arranged in the material extrudingdirection.

In other embodiments, the invention is directed to an apparatus formanufacturing a three-dimensional netted structure as described herein,comprising: a die, a mouthpiece of the die having a plurality of holes,the filaments being extruded downward from the die via the mouthpiece;and, drawing-down units partly-submerged in liquid, having the filamentsdrop in between; wherein the drawing-down units draw the filaments inbetween at a speed lower than the filament dropping speed, and thedistance between the drawing-down units is set smaller than the width ofthe assembly of the extruded filaments, characterized in that thedrawing-down units are arranged so that four surfaces of the assembly ofthe filaments contact the drawing-down units before or after thedrawing-down units are submerged.

In a class of this embodiment, the mouthpiece has a slit in addition tothe plurality of holes, the slit extending in the lengthwise directionof the mouthpiece such that the three dimensional netted structureadditionally comprises a substantially non-void-carrying sheet whichforms a wavy shape in the material extruding direction.

In a class of this embodiment, the mouthpiece has a region not providedwith holes so as to make a hollow portion in the three-dimensionalnetted structure arranged in the material extruding direction.

In other embodiments, the invention is directed to a method ofmanufacturing a three-dimensional netted structure as described herein,by extruding molten filaments of a thermoplastic resin downward from adie via a mouthpiece of the die having a plurality of holes, such thatthe filaments drop in between drawing-down units partly-submerged inliquid and the distance between the drawing-down units is set smallerthan the width of the assembly of the extruded filaments; drawing downthe assembly of extruded filaments at a speed lower than the filamentdropping speed and, cooling the resultant filaments with a liquid,characterized in that the drawing down is by drawing-down units arrangedso that four surfaces of the assembly of the filaments contact thedrawing-down units before or after the drawing-down units are submerged.

In a class of this embodiment, the mouthpiece has a slit in addition tothe plurality of holes, the slit extending in the lengthwise directionof the mouthpiece such that the three dimensional netted structureadditionally comprises a substantially non-void-carrying sheet whichforms a wavy shape in the material extruding direction.

In a class of this embodiment, the mouthpiece has a region not providedwith holes so as to make a hollow portion in the three-dimensionalnetted structure arranged in the material extruding direction.

In other embodiments, the invention is directed to a method ofmanufacturing a three-dimensional netted structure, the method beingapplied to form netted structures described herein.

In other embodiments, the invention is directed to a method ofmanufacturing a three-dimensional netted structure, comprising applyingthe apparatus described herein to form a netted structure.

In other embodiments, the invention is directed to a method ofmanufacturing a three-dimensional netted structure, comprising applyingthe apparatus described herein to form a netted structure describedherein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a three-dimensional netted structure ofan exemplary embodiment of the invention;

FIG. 2( a) is a longitudinal sectional view of the three-dimensionalnetted structure of an exemplary embodiment of the invention;

FIG. 2( b) is a longitudinal sectional view of a three-dimensionalnetted structure of another exemplary embodiment of the invention;

FIG. 2( c) is a longitudinal sectional view of a three-dimensionalnetted structure of another exemplary embodiment of the invention;

FIG. 2( d) is a longitudinal sectional view of a three-dimensionalnetted structure of another exemplary embodiment of the invention;

FIG. 2( e) is a longitudinal sectional view of a three-dimensionalnetted structure of another exemplary embodiment of the invention;

FIG. 2( f) is a longitudinal sectional view of a three-dimensionalnetted structure of another exemplary embodiment of the invention;

FIG. 2( g) is a longitudinal sectional view of a three-dimensionalnetted structure of another exemplary embodiment of the invention;

FIG. 3( a) is a longitudinal sectional view of the three-dimensionalnetted structure of another exemplary embodiment of the invention;

FIG. 3( b) is a side view of the three-dimensional netted structure ofanother exemplary embodiment of the invention;

FIGS. 4( a) to 4(g) are sectional views of a three-dimensional nettedstructure of another exemplary embodiment of the invention;

FIG. 5 is a perspective view of an apparatus for manufacturing thethree-dimensional netted structure of an exemplary embodiment of theinvention;

FIG. 6 is an explanatory drawing showing the condition of an operationof the apparatus for manufacturing the three-dimensional nettedstructure of an exemplary embodiment of the invention;

FIGS. 7( a) and 7(b) are a side view and a front view, respectively, ofendless conveyors in the same apparatus for manufacturing thethree-dimensional netted structure;

FIGS. 8( a) to 8(f) are side views of modified modes of endlessconveyors in the same apparatus for manufacturing the three-dimensionalnetted structure;

FIG. 9( a) is a plan view of endless conveyors for an apparatus formanufacturing a four-surface-molded three-dimensional netted structure;

FIG. 9( b) is a side view of the same apparatus for manufacturing thethree-dimensional netted structure;

FIG. 9( c) is a side view of another exemplary embodiment of theapparatus for manufacturing a four-surface-molded three-dimensionalnetted structure;

FIG. 9( d) is a plan view showing the condition of a four-surfacemolding operation carried out by the same apparatus for manufacturingthe three-dimensional netted structure;

FIG. 9( e) is a plan view showing the condition of a three-surfacemolding operation carried out by the same apparatus for manufacturingthe three-dimensional netted structure;

FIG. 10( a) is a plan view of endless conveyors in an apparatus of anindependent driving system for manufacturing a four-surface-moldedthree-dimensional netted structure;

FIG. 10( b) shows endless conveyors provided with sliding plates at endsurfaces thereof in an apparatus for manufacturing a three-dimensionalnetted structure;

FIGS. 11( a) to 11(h) are plan views and a front view showing variousexemplary embodiments of mouthpieces of a die;

FIGS. 12( a) and 12(b) are front views of modified modes of endlessconveyors, which are used for carrying out a four-surface moldingoperation, in an apparatus for manufacturing a three-dimensional nettedstructure;

FIG. 13( a) is a longitudinal sectional view of a three-dimensionalnetted structure of another exemplary embodiment of the invention;

FIG. 13( b) is a longitudinal sectional view of a three-dimensionalnetted structure of another exemplary embodiment of the invention;

FIG. 13( c) is a longitudinal sectional view of a three-dimensionalnetted structure of another exemplary embodiment of the invention;

FIG. 13( d) is a longitudinal sectional view of a three-dimensionalnetted structure of another exemplary embodiment of the invention;

FIG. 14( a) is a longitudinal sectional view of a three-dimensionalnetted structure of another exemplary embodiment of the invention;

FIG. 14( b) is a longitudinal sectional view of a three-dimensionalnetted structure of another exemplary embodiment of the invention;

FIG. 14( c) is a longitudinal sectional view of a three-dimensionalnetted structure of another exemplary embodiment of the invention;

FIG. 15 is a perspective view of the apparatus for manufacturing athree-dimensional netted structure of another exemplary embodiment ofthe invention;

FIG. 16( a) is a horizontal sectional view showing the portion of theapparatus for manufacturing a three-dimensional netted structureaccording to the invention which is in the vicinity of an upper part ofa mouthpiece of a complex die;

FIG. 16( b) is a front view of a lower portion of the complex dieaccording to an exemplary embodiment of the invention;

FIGS. 17( a) and 17(b) are drawings illustrating other exemplaryembodiments of the apparatus for manufacturing a three-dimensionalnetted structure;

FIGS. 18( a), 18(b) and 18(d) are plan views showing other exemplaryembodiments of mouthpieces of dies;

FIG. 18( c) is a front view of the mouthpiece shown in FIG. 18( d);

FIGS. 19( a) to 19(d) are plan views showing exemplary embodiments ofthe mouthpieces of the dies;

FIG. 20 is an explanatory drawing showing the condition of an operationof another exemplary embodiment of the apparatus for manufacturing athree-dimensional netted structure;

FIGS. 21( a) and 21(b) are side views and front views, respectively, ofrolls in the same apparatus for manufacturing a three-dimensional nettedstructure;

FIGS. 22( a) to 22(g) are side views of other embodiments of rolls inthe same apparatus for manufacturing a three-dimensional nettedstructure;

FIG. 23( a) is a front view of the three-dimensional netted structure(applied to a gardening cushioning material and the like) of anotherexemplary embodiment of the invention;

FIG. 23( b) is a plan view of the same three-dimensional nettedstructure;

FIG. 23( c) is a side view of the same three-dimensional nettedstructure;

FIG. 23( d) shows another exemplary embodiment of the three-dimensionalnetted structure;

FIG. 24( a) is a plan view of a mouthpiece of a die in another exemplaryembodiment of the apparatus for manufacturing a three-dimensional nettedstructure;

FIG. 24( b) is a front view thereof;

FIG. 24( c) is a plan view of a mouthpiece of another die;

FIG. 24( d) is a front view thereof;

FIG. 25 is an explanatory drawing showing the condition of use ofanother exemplary embodiment of the three-dimensional netted structure;

FIG. 26 is an explanatory drawing showing the condition of another useof another exemplary embodiment of the three-dimensional nettedstructure;

FIG. 27 is a construction diagram of a part of another exemplaryembodiment of the apparatus for manufacturing a three-dimensional nettedstructure;

FIG. 28 is an explanatory drawing showing the condition of an operationof an apparatus 601 for manufacturing a three-dimensional nettedstructure in an exemplary embodiment;

FIG. 29 shows a chute 604 in the exemplary embodiment; FIG. 29( a) is aplan view of a chute 604; FIG. 29( b) is a sectional view along the D-Dline of FIG. 29( a);

FIG. 30 shows a chute 804 in the exemplary embodiment; FIG. 30( a) is aplan view of a chute 804. FIG. 30( b) is a sectional view along the E-Eline of FIG. 30( a);

FIGS. 31( a) and 31(b) show a water level with respect to conveyor; and

FIG. 32 shows an exemplary embodiment wherein the water level is shownwith respect to conveyor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in FIGS. 1 and 2( a), a three-dimensional netted structure 1 isa three-dimensional netted structure the characteristics of which residein that the structure is a three-dimensional plate type netted structureformed out of a regenerated thermoplastic resin as a raw material or amain raw material, in which a plurality of filaments are helically andrandomly entangled and partly and thermally bonded together and have twoside surfaces, left and right end surfaces and upper and lower endsurfaces. It is preferable that the density of surface-side portions ofthree surfaces out of the side surfaces of this three-dimensional nettedstructure be relatively higher than that of the portion exclusive of thementioned surface-side portions. Namely, referring to FIG. 2( a), thethree-dimensional netted structure 1 is in this embodimentthree-surface-molded. In this structure, regions thereof which extendinward from the opposite surfaces thereof by a predetermined distanceare molded to a high density, and the density of a region which extendsin a central inner portion of the netted structure is set lower than thementioned density. Thus, the remaining one surface of the structure hasa non-straight extending surface. Therefore, this netted structure hasan advantage in being not subjected to a process in a later stage. Inshort, a pair of surfaces of a large width and one side surface areforcibly molded by endless conveyors and the like which will bedescribed later, and the edges of these surfaces are formed moreesthetically pleasing than that of the other surface.

In this embodiment, flaked or chipped PET bottles are used as a rawmaterial or a main raw material of the regenerated thermoplastic resin.The raw material is obtained by pulverizing unmodified PET bottles,melting the pulverized products, and forming the molten product intoflakes. This material is suited to the recycling promoting age. When thematerial is not a recycled product but a genuine product, themanufacturing cost per 1 square meter of the netted structure doublesdue to the dry crystallization of or the removal of waste from thematerial. The material used in this embodiment allows for a reduction ofthe product scrapping cost. However, this embodiment can also be appliedto a thermoplastic resin and the like other than regenerated materialsof this kind. For example, polyolefines, such as polyethylene,polypropylene, etc., polyesters, such as polyethylene terephthalate,etc. polyamides, such as nylon 66, etc, polyvinyl chloride, polystyrene,a copolymer and an elastomer obtained by copolymerizing these resins asbase materials, a material obtained by blending these resins, and someother similar materials.

The three-dimensional netted structure, is used mainly as a cushioningmaterial, a shock absorbing material, a moisture absorbing material, asound absorbing material (to be provided under a floor material, in aninner portion of a structure and inside a wall), a heat insulatingmaterial (inner and outer heat insulating purposes), a wall surfacematerial, a roof gardening material, a concrete and mortar crackingpreventing material, interior finishing material for automobiles, andhas some other uses. This netted structure can also be applied to aninner portion of a double wall.

When a fire resistant material is mixed with the three-dimensionalnetted structure by holding the three-dimensional netted structurebetween nonwoven cloths or by attaching such cloths thereto, andapplying fire resistant paint to the netted structure, so as to givefire resistance to the three-dimensional netted structure, the resultantnetted structure becomes more preferable as a heat insulating buildingmaterial, a sound absorbing building material and the like.

The netted structure in this embodiment is molded so as to have asubstantially uniform density at an inner portion thereof. The apparentdensity of this embodiment is preferably 0.02 to 0.9 g/cm³(corresponding to a percentage of void of 36 to 98.4%), and especiallypreferably 0.05 to 0.15 g/cm³. The three-dimensional netted structure 1preferably has, for example, a width of 0.1 m to 2 m and a thickness of5 mm to 200 mm, and extends endlessly in the lengthwise direction. Thenetted structure is cut to a suitable length (for example, 90 mm) butthe sizes of the netted structure are not limited to the examplesmentioned above.

Referring to FIG. 2( b), a three-dimensional netted structure 2 ofanother exemplary embodiment is four-surface-molded, and all thesurfaces of the netted structure extend straight. This netted structureis formed so that the density of the regions thereof which correspond tothose of the three-dimensional netted structure 1, and which extendinward from the left and right surfaces of the netted structure towardan inner portion thereof by a predetermined distance, becomes high, andso that the density of the region of the netted structure which is at acentral inner portion thereof be set lower than the mentioned density.Namely, the regions of the netted structure which extends from all thesurfaces thereof except the upper and bottom surfaces thereof to aninner portion of the netted structure by a predetermined distance aremolded to a density higher than the above-mentioned density.

In another embodiment, a three-dimensional netted structure 3 has asurface of modified shapes or a polyhedral surface. With reference to,this type of netted structures include, for example, a netted structure3A provided with a convex surface (FIG. 4( a)) a netted structure 3Bprovided with a concave surface (FIG. 4( b)), a netted structure 3Cprovided with a plurality of continuously formed projecting and recessedportions (FIG. 4( c)), a netted structure 3D provided with a pluralityof saw-tooth-like portions (FIG. 4( d)), a netted structure 3E providedwith a plurality of wavy portions (FIG. 4( e)), a netted structure 3Fprovided with rounded corner portions (FIG. 4( f)), a netted structure3G provided with cut corner portions of a predetermined angle, e.g., 45°(FIG. 4( g)), or a suitable combination thereof, etc.

In the field of construction, various types of netted structures aredemanded as products, and these embodiments can meet a demand for suchnetted structures. It is considered that forming netted structures ofcomplicated shapes causes various uses thereof to be newly found.Especially, forcibly molding three or four surfaces of thethree-dimensional netted structure as in the above-described first andsecond modes of embodiment enables the various demands for the productsto be met. Furthermore, in order to obtain netted structures ofmiscellaneous surface shapes, netted structures are generally cut ormolded so as to provide surfaces of modified shapes thereon on a laterstage. According to this mode of embodiment, products can be providedinstantly without finishing the netted structure as to the shape andsizes, which the products demand, on a later stage, so that a laterstage can be rendered unnecessary.

The three-dimensional netted structure 4 (shown in FIG. 2( c)) isprovided with a single or a plurality (two in this embodiment) of hollowportions 4A, 4B, and aims at further reducing the manufacturing cost.

The three-dimensional netted structure 5 (shown in FIG. 2( d)) hasregenerated members 5C, 5D of the same or different materials, such asplate type regenerated veneer members, plate type members of regeneratedshredder dust and the like inserted in hollow portions 5A, 5B identicalwith the hollow portions 4A, 4B of the three-dimensional nettedstructure 4. This embodiment aims at improving the sound absorbability,heat insulating characteristics, cushioning characteristics and the likeof the netted structure by using regenerated plate members.

In the three-dimensional netted structure 6 (shown in FIG. 2( e)), thesound absorbing characteristics, heat insulating characteristics,cushioning characteristics and impact resistance are improved byincreasing the density of parts of the inner portion of thethree-dimensional netted structure 1 in the direction of the thicknessthereof, and thereby partly forming a single or a plurality (e.g., threein this embodiment) of beam-like high-density regions 6A, 6B and 6C atpredetermined intervals.

In the three-dimensional netted structure 7 (shown in FIG. 2( f)), thesound absorbing characteristics, heat insulating characteristics,cushioning characteristics and impact resistance thereof are improved byincreasing the density of parts of the inner portion thereof in thewidthwise direction thereof, and thereby partly forming a plurality (onein this embodiment) of or a single high-density region 7A.

In the three-dimensional netted structure 8 (shown in FIG. 2( g)), thesound absorbing characteristics, heat insulating characteristics,cushioning characteristics and impact resistance are improved by forminga wavy high-density region 8A in an inner portion of thethree-dimensional netted structure 7.

In the three-dimensional netted structure 9 (shown in FIG. 3( a)), thesound absorbing characteristics, heat insulating characteristics,cushioning characteristics and impact resistance are improved by forminga sheet 9A (a non-void-carrying region) in a predetermined widthwiseextending inner portion of the three-dimensional netted structures 1 or2. Around the sheet 9A, filaments (resin threads) are entangled with oneanother. The sheet 9A may be provided fully in the lateral direction asshown in the drawing, and also partly, for example, in the centralportion and the like.

The sheet 9A in the three-dimensional netted structure 9 (shown in FIG.3( b)) is wave form in general and the sound absorbing characteristics,heat insulating characteristics, cushioning characteristics and impactresistance of the netted structure are improved. The reason for why thesheet 9A can be molded in wave form resides in that a draw-down speed ofrolls is lower than a resin thread dropping speed, as will be describedin more detail later. The intervals, height and width of the waves ofthe sheet 9A differ depending upon the manufacturing conditions, and arenot limited to those shown in the drawing. When the intervals of thewaves of the sheet 9A are small, the waves are bonded to one another insome cases. The three-dimensional netted structure 9 can be manufacturedby using a slit (linear through hole) 75 a shown in FIG. 11( e).

Although illustrations are omitted, the invention can also be applied tothree-dimensional netted structures of modified cross-section shapes,such as a triangular cross-section shape, a Y-type cross-section shapeand the like.

Apparatus for Manufacturing a Three-Dimensional Netted Structure

An apparatus 10 for manufacturing a three-dimensional netted structurewill now be described.

As shown in FIG. 5, the apparatus 10 for manufacturing athree-dimensional netted structure, comprises: an extrusion moldingmachine 11, a pair of endless conveyors 14, 15 (shown in FIG. 7)provided with endless members 12, 13, a motor 16 adapted to drive theendless members 12, 13, a transmission 17 formed of a chain and a gearand adapted to change a moving speed of the endless members 12, 13, awater tank 18 adapted to partly submerge the two endless conveyors 14,15 therein, a control unit 19, and other meters, etc.

The endless members 12, 13 are formed by fixing with screws (not shown)a plurality of metal plate members 21 (made of stainless steel and thelike in this embodiment) to a plurality of endless chains 12 a, 13 a(two for each conveyor) (see FIGS. 7( a) and 7(b)) with a predeterminedwidth of clearance 22 (refer to FIG. 8( a)) left therebetween. Insteadof these plate members, a belt 23 of a stainless steel mesh (metal net)which does not have the clearance 22 may also be used as shown in FIG.8( b). This mesh belt is formed by combining spiral wires with rods(power ribs), and various types of mesh belts are formed by varying theshapes, diameters and pitch of these two elements. Such mesh belts movesmoothly, keep the smooth belt surfaces horizontal excellently, standuse in hot temperature condition excellently, and are repaired simply.

As shown by dotted lines in FIG. 7, stainless mesh belts 23 passedaround outer circumferences of the endless members 12, 13 can also beused in practice, and are preferably used when it is desirable toprevent the occurrence, which is ascribed to the presence of theclearance 22, of recessed and projecting portions on the mesh belt. Thecross section of the plate member 21 is rectangular, and variousmodified modes of plate members 21 are conceivable, which include aconvex plate member 24 (FIG. 8( c)), a concave plate member 25 (FIG. 8(d)), a saw-tooth plate member 26 (FIG. 8( e)), a continuously recessedand projecting plate member 27 (FIG. 8( f)), etc.

As shown in FIG. 7, the endless conveyor 14 is provided with a drivingshaft 14 b having a sprocket 14 a around which the endless chain 12 aprovided vertically is passed, and a driven shaft 14 d having a sprocket14 c. The endless conveyor 15 is driven synchronously with the endlessconveyor 14, and provided with a driven shaft 15 b mounted with asprocket 15 a around which the endless chain 13 a is passed, and adriven shaft 15 d mounted with a sprocket 15 c.

As shown in FIG. 5, the extrusion molding machine 11 includes acontainer 31, a raw material feed port 32 provided on an upper portionof the container 31, a die 33, a mouthpiece 34 capable of being fixeddetachably to a lower end portion of the die 33. A range of thetemperature in an inner portion of the die of the extrusion moldingmachine 11 can be set to between 100 and 400° C., and an extrusion rateof the machine 20 to 200 kg/hr and the like. A range of the pressure inthe die is 0.2 to 25 MPa, which is equal to, for example, a dischargepressure of a 75 mm screw.

When the thickness of the three-dimensional netted structure exceeds 100mm, the equalization of the pressure in the die by a gear pump and thelike is needed in some cases. Therefore, it becomes necessary that thepressure in the die be increased by a gear pump and the like so as todischarge filaments uniformly from the whole region of the interior ofthe die. To meet the requirement, the surfaces of the endless conveyors14, 15 are formed so that these surfaces can be moved freely so as toset the shape of a three-dimensional netted sheet. This enables aproduct having desired density and strength to be manufactured inaccordance with the shape (density or diameter of the holes H) of themouthpiece 34 of the die 33 and a transfer speed of the endlessconveyors 14, 15, and various demands for the products to be met.

An apparatus 50 for manufacturing a three-dimensional netted structurewhich is made of such a four-surface-molding machine as shown in FIGS.9( a) and 9(b) will now be described. This apparatus 50 formanufacturing a three-dimensional netted structure is provided withendless conveyors 54, 55 having rotary shafts 54 a, 55 a whichcorrespond to the endless conveyors 14, 15 used in a two-surface-moldingoperation, shown in FIG. 7, and a pair of rolls 56, 57 disposed atlengthwise end portions of the endless conveyors 54, 55 and havingrotary shafts 56 a, 57 a extending at right angles to the shafts of theendless conveyors. The rotary shaft 54 a is mounted with bevel gears 54b, 54 c, while the rotary shafts 56 a, 57 a are also mounted with bevelgears 56 b, 57 b. The bevel gears 54 b, 54 c and the bevel gears 56 b,57 b are meshed with each other, and the rotary shafts 54 a, 55 a aredriven synchronously by a motor M via a chain C. Therefore, the rotaryshafts 56 a, 57 a are also driven synchronously. The other end portionsof the rotary shafts 56 a, 57 a are supported on bearings 58 a, 58 b.

As shown in FIG. 9( c), the apparatus may be an apparatus formed byarranging a pair of short endless conveyors 59 a, 59 b, the constructionof which is identical with the endless conveyors 54, 55, at right anglesto rotary shafts of rolls. In this case, the molding of a product can bedone more precisely, and the dimensional accuracy of a product isimproved.

As shown in FIG. 9( d), the manufacturing of a three-dimensional nettedstructure can be done by using four-surface-molding techniques. Thethree-surface-molding of the product can also be done by using thementioned techniques as shown in FIG. 9( e). Namely, when a certain typeof three-dimensional netted structure is manufactured, two systems ofdies are provided, and filaments are extruded in parallel. As a result,the productive efficiency of the netted structure doubles.

As shown in FIG. 10( a), an apparatus of a modified mode can be alsoused which is formed by providing driving power sources (motors) insteadof the previously-mentioned synchronous driving system so that endlessconveyors 64, 65 and rolls 66, 67 (endless conveyors also serve thepurpose) are driven independently of each other. Namely, in order tocarry out three-surface or four-surface-molding operation, endlessconveyors 64, 65 having rotary shafts 64 a, 65 a, and a pair of rolls66, 67 arranged at lengthwise end portions of these endless conveyors64, 65, and having rotary shafts 66 a, 67 a extending at right angles tothose of the endless conveyors are provided. The rotary shafts 66 a, 67a are also provided with respective motors M so that these rotary shaftsare driven independently of each other. The other end portions of therotary shafts 66 a, 67 a are supported on bearings 68 a, 68 b.

As shown in FIG. 10( b), which shows another modified mode of theapparatus, in which a driving mechanism can be simplified by removingsuch two rolls 66, 67, two rotary shafts 66 a, 67 a, two bearings 68 a,68 b and two motors M as are provided in the preceding example, andproviding sliding curved plates 69 a, 69 b, the surfaces of which arecoated with polytetrafluoroethylene, in positions in which the rolls 66,67 were placed. These curved plates 69 a, 69 b are arcuate in sideelevation and positioned so that a distance between these curved platesdecreases gradually from upper portions thereof toward lower portionsthereof. The curved plates are formed to a rectangular shape in plan.

The holes of the mouthpiece 34 are downwardly made in series, from whichfilaments come out downward. The holes may be arranged at regularintervals or at non-regular intervals. The holes may employ staggered,orthogonal and various other types of configurations. When it is desiredthat the arrangement density of the holes be changed, a method ofpositively increasing the arrangement density thereof in end regionsonly is used in some cases. Changing the mode of the mouthpiecevariously enables various demands for the products to be met.Mouthpieces of a multiplicity of specifications can be used practicallywhich include, for example, a mouthpiece 71 (having holes H accountingfor 90% of the area of the mouthpiece 71) (refer to FIG. 11( a)) of 1.0m×180 mm in which about 3500 holes H of 0.5 mm in diameter are made, amouthpiece 72 (refer to FIG. 11( b)) in which the density of the holes His set high only in a circumferential portion 72 a thereof, a mouthpiece73 (refer to FIG. 11( c)) in which the density of the holes H offrame-forming portion 73 b is increased so that the frame-formingportion constitutes series-connected frames, a mouthpiece 74 (refer toFIG. 11( d)) in which slits (linear through holes) 74 a to 74 c inaddition to a multiplicity of holes H are formed so that the slitsextend in parallel with shorter sides of the mouthpiece, a mouthpiece 75(refer to FIG. 11( e)) in which a slit (linear through hole) 75 a inaddition to a multiplicity of holes H is formed so that the slit extendsin the lengthwise direction of the mouthpiece, a mouthpiece 76 (refer toFIG. 11( f)) and the like in which a slit (linear through hole) 76 a inaddition to a multiplicity of holes H is formed so that the slit extendsin a position near a lengthwise side of the mouthpiece, and similarother mouthpieces, and a mouthpiece 77 (refer to FIGS. 11( g) and 11(h))and the like which have regions 77 c, 77 d not provided with the holes Hso as to make hollow portions therein, and which is provided under theseregions with cross-section square introduction members (pipes, etc.) 77a, 77 b projecting downward therefrom. The density of the holes H formedin these mouthpieces is preferably 1 to 5/cm².

Method of Manufacturing a Three-Dimensional Netted Structure

This three-dimensional netted structure 1 is manufactured in thefollowing manner. First, flakes of regenerative PET bottles are heatedand dried for preventing the same from being hydrolyzed, and chemicalsfor finishing the resultant product, or an antibacterial agent and thelike are added suitably in some cases. When filaments come out flat fromthe mouthpiece 34 in the downward direction, the filaments are entangledhelically owing to the entangling actions of the endless members 12, 13of the endless conveyors 14, 15. The filaments start being entangled atthe portions thereof which contact the surfaces of the endless members12, 13 at the entangling-starting time. The density of the portions ofthe filaments which are entangled is high, and that of the portionsthereof which are not entangled is low.

Next, as shown in FIG. 6, a three-dimensional netted structure 1, anobject netted structure is manufactured by extruding a moltenthermoplastic resin downward from a plurality of dies 33, having theextruded filaments of the resin drop naturally to a position between apair of partly submerged endless conveyors 14, 15, and drawing down thefilaments of the resin at a speed lower than the filament droppingspeed. When this netted structure 1 is thus manufactured, the twoendless conveyors 14, 15 are arranged so that a distance between theendless conveyors is set smaller than a width of an assembly of theextruded filaments of the molten resin, and so that both or one surfaceof the assembly of the filaments of the molten resin contacts theendless conveyors 14, 15 before or after these conveyors are submerged.

Both or one of the surface portion of the assembly of the moltenthermoplastic resin drops on the endless conveyors 14, 15, and moves toan inner side of the assembly, so that the surface portion of theassembly becomes dense. Therefore, the percentage of void of the surfaceportion becomes lower than that of a central portion which drops as itis into the water. It is a matter of course that the surface portion inwhich the percentage of void becomes low comes to have an increasednumber of nodes as compared with the central portion having a highpercentage of voids, and that the tensile strength of the surfaceportion becomes noticeably high. The surface portion having a lowpercentage of void comes to have a small area of voids, and forms animpact absorbing layer and a soundproofing layer.

A result showing that a percentage of void of the three-dimensionalnetted structure 1 as a whole high enough to have the netted structurefunction well is in the range of 50% to 98%, though these levels differwith the condition of execution of works on a job site was obtained. Inshort, it is considered that, when the density of the netted structureis high, sounds are blocked. A result showing that, in order to have thethree-dimensional netted structure function as a recycled soundabsorbing building material, a cushioning material, a heat insulatingmaterial and the like, the percentage of void thereof may be setpreferably to not lower than 70% was obtained. In short, when thepercentage of void is lower than 70%, the impact absorbing effect,soundproofing effect, heat insulating effect and cushioningcharacteristics of the netted structure are not in some cases soimproved as was expected. It is recommended that the three-dimensionalnetted structure 1 may be designed suitably with the percentage of voidset in the range of 70% to 98% in accordance with the use of the nettedstructure.

A sound absorbing material and a cushioning material have a preferablepercentage of void of 85 to 98%, an impact absorbing material to beprovided under a floor 40 to 80%, and a collision-preventing impactabsorbing material 60 to 90%. A preferable range of the percentage ofvoid varies with the use of the netted structure.

The percentage of void=100%−{(B÷A)×100%}, wherein A represents a productof the specific gravity of the resin and the volume of thethree-dimensional netted structure; and B represents the weight of thenetted structure.

The thermoplastic resin used in this method is obtained by pulverizingPET bottles into flakes, which are used as a raw material or a main rawmaterial. However, resins including a polymer, such as polypropylene,etc. or a resin obtained by blending a plurality of kinds of polymerstogether, etc. may be used as a main raw material without trouble aslong as the resin can be processed by a regular extrusion moldingmachine.

In the step of forming three-dimensional netted structures to finalmodified shapes, a mechanism for equalizing the inner pressure of thedies, and drawing down an assembly of filaments at two, three or foursurfaces thereof or at an intermediate portion thereof is used. Thisenables such characteristics to be given to this netted structuremanufacturing method that include its capability of attaining anapparent density of a product of 0.02 to 0.9 g/cm³, changing thefilaments of the molten resin from a randomly and helically entangledstate into a state of a flat plate, and turning the surface portions ofthe three-dimensional netted structure including the front, rear, leftend and right end surfaces with respect to the direction of thethickness thereof into flat surfaces and surfaces of modified shapes,i.e., projecting and recessed surfaces. The mouthpiece of a die used toform the three-dimensional netted structure is made so that a nettedstructure of a rod type shape, modified shapes (shape of a pipe and ashape of the letter “Y”), etc. and a netted structure of various othershapes devised by combining these shapes together can be obtained.

The three-dimensional netted structure is subjected to compression bythe rolls of a draw-down machine to obtain a super-dense sheetstructure. The inner pressure of the dies used to have the regeneratedPET resin discharged uniformly from the dies is equalized, and the threeor four surfaces of an assembly of filaments of a molten resin extrudedwhen the three-dimensional netted structure is manufactured is broughtinto contact with the draw-down conveyors by which these surfaces areshaped. In short, the assembly of filaments of the molten regeneratedPET resin is formed at the three or four surfaces thereof to shapes of afinal product. For example, a resin filament assembly is drawn up asnecessary around polygonal conveyors to form a product. In one of themethods of obtaining a three-dimensional netted sheet, filaments of amolten resin are extruded downward from a plurality of dies, and droppednaturally onto water surface or to a position between partly-submergedconveyors. Thus, a randomly and helically entangled filament assembly ismade, which forms a three-dimensional netted sheet.

It was ascertained that, when the speed of the endless conveyors wasvaried, the density of a sheet of 1.0 m in width and 100 mm in thicknessvaried.

It was further ascertained that the density of the sheet varied inaccordance with the variation of a discharge rate of the extruder.

The mouthpiece 34 having about 3500 substantially regularly spaced holesH of 0.5 mm in diameter was fixed to the dies 33 having an area of 1.0m×180 mm in a uniaxial extruder having a screw of 75 mm in diameter. Thewater tank 18 having a water level in a position about 120 mm below thedies 33 is provided, and a pair of endless conveyors 14, 15 of 1.2 m inwidth were installed substantially vertically in the tank with aclearance of 50 mm left therebetween, in such a manner that upperportions of the endless conveyors project upward from the water level byaround 40 mm.

In this apparatus, the molten resin filament assembly was extruded fromthe mouthpiece 34 at an extrusion rate of 120 kg/hr to a positionbetween the endless conveyors 14, 15 so that two surfaces of the moltenresin filament assembly dropped on the endless conveyors, by controllingthe temperature of the dies 33 so that the temperature of the resinbecame 240° C. while plasticizing a regenerated PET resin by heating thesame. During this time, the draw-down speed of the endless conveyors 14,15 was set to 0.7 m/min. The molded product held between the endlessconveyors 14, 15 and moved down changed its direction in a lower portionof the interior of the water tank 18, and was moved from the side of thewater tank which is opposite to the extruder to the water surface. Whenthe molded product came out of the water tank 18, the water thereon wasblown off with compressed air or by a vacuum pump.

The three-dimensional netted structure thus obtained had a width of 1.0m, a thickness of 50 mm, and a density of 0.07 g/cm³ to 0.14 g/cm³. Thisnetted structure may be used as a heat insulating material, a groundmaterial, and a sound absorbing material, and for a drain pipe, etc.

The above-described three-dimensional netted structure 1 and apparatus10 for manufacturing the same netted structure enable a finishingoperation on a later stage to be omitted, the degree of straightness ofsurfaces of the netted structure to be improved, a demand for a nettedstructure having modified shapes to be met, and the durability of thenetted structure to be improved.

Owing to this mode of embodiment, the PET bottles which do not have usesin the existing circumstances newly find a use as materials for athree-dimensional netted structure, and it is considered that a recoverypercentage of the PET bottles will increase. This causes the recyclingof the PET bottles to be greatly promoted.

FIG. 12 shows a modified mode of the apparatus 50 for manufacturing afour-surface-molded three-dimensional netted structure, and FIG. 12( a)is a drawing corresponding to FIG. 9( b) and shows a pair of rolls 56,57 as described above which have a single or a plurality of projections90 a to 90 c on the respective surfaces thereof (the illustrations ofthe roll 57 and its projections are omitted). These projections areformed so as to provide recesses in side surfaces of thethree-dimensional netted structure. Each of the projections 90 a to 90 chas angular portions and an arcuate side portion in cross section.Although the recesses referred to above and formed in the side surfacesof the netted structure ought to become rectangular theoretically, therecesses become curvilinear since the resin filaments drop into thespace between the endless conveyors from above as above-mentioned,causing blind regions in which the resin filaments do not enter tooccur. In short, the recesses become roundish.

FIG. 12( b) corresponds to FIG. 9( c), and shows endless conveyors (theillustrations of the endless conveyor 55 and its projections areomitted) formed by providing a single or a plurality of projections 96on the surfaces of two endless belt conveyors like those of theabove-mentioned belt conveyors 54, 55, etc. This modified apparatus canalso be formed by incorporating cams and springs in the rotary bodies,such as the above-mentioned rolls 56, 57 or endless conveyors 54, 55 sothat the projections are forced out in the outward direction by the camssynchronously with the rotations of the rotary bodies. This enables theoccurrence of blind regions to be reduced, and more precise recesses tobe formed. Since the construction of the other parts is identical withthat of the corresponding parts of the apparatus shown in FIGS. 9( b)and 9(c), the illustrations and description of the latter will beutilized and quoted.

The demands for the recycling of the products of the three-dimensionalnetted structures have become diversified, and cannot be met under thepresent circumstances in some cases. For example, when it is desiredthat a mixture of not smaller than two kinds of regenerated resins beutilized, some of these raw materials prove separable during recyclingoperations therefor, and some prove non-separable. Non-separable rawmaterials are sometimes mixed into a starting material, and therecycling and utilizing of raw materials actually become impossible insome cases in spite of the effort made to recycle the materials. Thereare various cases where the same raw material is used for a certainpurpose, which include a case where changing the shape of a product isdesired, such as a case where forming sparse and dense regions isdesired, a case where forming hollow portions on a later stage isdesired and similar cases, or a case where improving the moldability ofthe materials is desired. The below-described embodiment is carried outso as to prevent troubles from occurring in the regeneration of athermoplastic resin, and attain the easiness of changing the shape of aproduct.

A three-dimensional netted structure 101 is a plate typethree-dimensional netted structure, the characteristics of which residein that the netted structure is formed by using a regeneratedthermoplastic resin as a raw material or a main raw material, and has aplurality of filaments helically and randomly entangled and partly andthermally bonded together, as shown in FIG. 13( a). This nettedstructure is made of an inner region 101 a and an outer region 101 b ofthe same or different raw materials. A boundary between the inner region101 a and outer region 101 b is shown by a solid line. The solid line isan imaginary line showing the boundary, and the same applies to theother modes of embodiment which will be described later. It ispreferable that the densities of two, three or four surface portions ofthis three-dimensional netted structure may be relatively higher thanthat of the portion of the netted structure which is exclusive of thesesurface portions. Namely, the three-dimensional netted structure 101(refer to FIG. 13( a)) of this embodiment is two-surface-molded.

This netted structure is molded so that the density of regions thereofwhich extend from the opposite surfaces thereof toward an inner portionthereof by a predetermined distance is high. The density of an innerpart of the central portion thereof is set lower than the mentioneddensity, and the other non-surface-molded surfaces are notstraight-formed. Therefore, it becomes unnecessary that this nettedstructure may be processed on a later stage. In short, a pair ofsurfaces of a large width and one side surface of the netted structureare forcibly molded by endless conveyors which will be described later,and edges of these surfaces are set more esthetically pleasing thanthose of the other surfaces.

A three-dimensional netted structure 102 (refer to FIG. 13( b)) is athree-surface-molded netted structure, in which all the surfaces exceptthe end surfaces and one side surface are set straight. The regionsextending from all the surfaces of the netted structure except the rightside surface thereof toward an inner portion thereof by a predetermineddistance are molded to a high density. This netted structure is made ofan inner region 102 a and an outer region 102 b of the same or differentraw materials.

A three-dimensional netted structure 103 (refer to FIG. 13( c)) isfour-surface-molded, in which all the surfaces thereof except an endsurface thereof are set straight. This netted structure is formed bymolding the regions, which extend from the left and right side surfacesof the same netted structure as that of the first mode of embodiment tothe inner part of the central portion thereof by a predetermineddistance, to a high density with the density of the region in the innerpart of the central portion of the netted structure set lower than thementioned density. Namely, the regions extending from all the sidesurfaces of the netted structure toward the inner portion thereof by apredetermined distance are molded to a high density. This nettedstructure is made of an inner region 103 a and an outer region 103 b ofthe same or different raw materials.

A three-dimensional netted structure 104 (refer to FIG. 13( d)) is athree-dimensional netted structure provided with a single or a pluralityof (one in this embodiment) hollow portions 104 c, and formed for thepurpose of further reducing the cost and for some other purposes. Thisnetted structure is made of an inner region 104 a and an outer region104 b of the same or different raw materials.

A three-dimensional netted structure 105 (refer to FIG. 14( a)) isformed of three layers of regions 105 a, 105 b and 105 c of the same ordifferent raw materials. The raw materials of all of the three layers ofregions may be different. The raw materials of the regions 105 a, 105 cmay be identical, and that of the region 105 b may be different. The rawmaterials of the three layers of regions may be all identical. Thenetted structure is divided into three layers of regions 105 a, 105 band 105 c in the lengthwise direction thereof.

A three-dimensional netted structure 106 (refer to FIG. 14( b)) is madeof two layers of regions 106 a, 106 b of the same or different rawmaterials. The raw material of the two layers of regions 106 a, 106 bmay be different or identical. This netted structure is divided into twolayers of regions 106 a, 106 b in the lateral direction thereof.

A three-dimensional netted structure 107 (refer to FIG. 14( c)) of asixteenth mode of embodiment is made of two layers of regions 107 a, 107b of the same or different raw materials. The raw materials of the twolayers of regions 107 a, 107 b may be different or identical. Thedirection in which this netted structure is divided into these regionsis that of the thickness of the netted structure unlike the direction inwhich the fourteenth and fifteenth modes of embodiment are divided.

In the embodiment shown in FIG. 3, a high-density sheet 9A (asubstantially non-void-carrying filled region) can be provided partly ina predetermined position in the lateral direction in the embodiment byforming the sheet and the other region by different extrusion moldingmachines through different paths. The description of this embodimentwill be quoted from that given previously with respect to the embodimentof FIG. 3.

Beside these netted structures, netted structures of modifiedcross-section shapes, such as a triangular shape, a shape of the letter“Y”, etc., the illustrations of which are omitted, can also be formed inpractice. As mentioned above, when a raw material is supplied to notsmaller than two regions provided on the mouthpiece, the regulation ofthe manufacturing conditions, such as the temperature of the rawmaterial, extrusion rate of the filaments, etc. can be made easily.

An apparatus 110 for manufacturing a three-dimensional netted structure2 will now be described.

This apparatus 110 for manufacturing a three-dimensional nettedstructure comprises, as shown in FIG. 15, an extrusion molding machine111, a pair of endless conveyors 114, 115 provided with endless members112, 113, a motor 116 for driving the endless members 112, 113, atransmission 117 formed of chains and gears and adapted to change themoving speed of the endless members 112, 113, a water tank 118 forsubmerging parts of the endless conveyors 114, 115 therein, a controlunit 119 and meters, etc.

The description of endless members 112, 113, etc. will be described byquoting that given previously with respect to endless members 12, 13.

As shown in FIG. 15, the extrusion molding machine 111 is formed ofcontainers 131 a, 131 b storing therein the same or different rawthermoplastic resin materials, raw material supply ports 132 a, 132 bprovided at upper portions respectively of the containers 131 a, 131 b,raw material supply pipes 133 a, 133 b connected to the containers 131a, 131 b respectively, a complex die 135 (refer to FIG. 16) connected tothe raw material supply pipes 133 a, 133 b via packings 134 a, 134 b, amouthpiece 136 (refer to FIG. 16) detachably fixable to a lower endportion of the complex die 135, etc. The raw material supply pipe 133 abranches at an intermediate portion thereof into a plurality of (four inthis embodiment) pipe members striding over the raw material supply pipe133 b. The lower end portions of the branches of the raw material supplypipe 133 a are arranged around that of the raw material supply pipe 133b.

As shown in FIGS. 16( a) and 16(b), the complex die 135 has a frame typepartition wall 139 in an inner region of an outer frame 138 so that theinterior of the complex die 135 is divided into two chambers 137 a, 137b, i.e., the complex die is formed so that the same kind of raw materialor two different kinds of raw materials supplied thereto via the rawmaterial supply pipes 133 a, 133 b are not mixed with each other. Evenwhen the raw material supplied through these supply pipes is the same,it is preferable to provide the partition wall 139 for the purpose ofregulating the extrusion rates separately. The particular parts of theinterior of the die of the extrusion molding machine 111 are formed byutilizing the corresponding parts of the first mode of embodiment.Although the raw material supply pipe 133 a is made to branch into fourmembers, the pipe may also be made to branch into a suitable number ofmembers, such as two members (refer to FIG. 17( a)), three members(refer to FIG. 17( b)), etc.

A mouthpiece 136 has not smaller than two regions so that a raw materialis supplied thereto separately. Therefore, the regulation of theextrusion speed or extrusion rate of filaments is made very easily, andthe moldability of the raw material is improved remarkably. The detailsof a description of the mouthpiece will be given for comparison byquoting the corresponding parts of the description of apparatus 10. Inthis embodiment, a mouthpiece 171 (the area of the region thereof whichis provided with holes H accounts for 90% of a total area of themouthpiece 171) (refer to FIG. 18( a)) having the holes at substantiallyregular intervals or at suitable intervals is used. In this mouthpiece171, an inner region 171 a and an outer region 171 b are defined by apartition wall 171 c shown by a broken line, and filaments of the sameor different materials are extruded separately and independently fromthese regions correspondingly to raw material supply pipes 133 a, 133 b.

A mouthpiece 172 (refer to FIG. 18( b)) may also be used, in which aninner region 172 a and an outer region 172 b which are provided with amultiplicity of holes H are defined by a partition wall 172 c shown by abroken line. The inner region 172 a is formed in a deflected manner withrespect to the outer region 172 b so that the filaments corresponding tothe inner region 172 a are separated easily.

A mouthpiece 173 (refer to FIGS. 18( c) and 18(d)) may also be used. Aninner region 173 a and an outer region 173 b which are provided with amultiplicity of holes H are defined by a partition wall 173 c shown by abroken line. The inner region 173 a is held between the pair of outerregion 173 b. In order to form hollow portions in this mouthpiece,regions 173 d, 173 e which do not have holes H are provided in theportions thereof which correspond to the hollow portions, andcross-section square introduction members (pipes and the like) 173 f,173 g extending downward are provided on lower portions of the tworegions.

A mouthpiece 174 (refer to FIG. 19( a)) may be also used, in which anupper region 174 a, a central region 174 b and a lower region 174 cwhich are provided with a multiplicity of holes H are defined bypartition walls 174 d, 174 e shown by broken lines to form three stages(three layers) of regions.

A mouthpiece 175 (refer to FIG. 19( b)) may be also used, in which anupper region 175 a and a lower region 175 b which are provided with amultiplicity of holes H are defined by a partition wall 175 c shown by abroken line to form two stages (two layers) of regions.

A mouthpiece 176 (refer to FIG. 19( c)) may be also used, in which aleft region 176 a and a right region 176 b which are provided with amultiplicity of holes H are defined by a partition wall 176 c shown by abroken line to form two rows (two layers) of regions.

A mouthpiece 177 (refer to FIG. 19( d)) may be also used, in which aregion 177 a provided with a multiplicity of holes H, and a slit (linearhole) 177 b formed in a suitable portion, such as a central portion,etc. so as to extend parallel to a predetermined direction (lengthwisedirection in this example) are defined by partition walls 177 c shown bybroken lines. The slit 177 b exists in a region between the partitionwalls 177 c shown by broken lines. The width, length or position of theslit (linear hole) 177 b can be suitably selected. When a raw materialis supplied from the same die to the region 177 a having many holes Hand slit (linear hole) 177 b, the wavy form of FIG. 3( b) is deformed,and the moldability of the material is deteriorated in some cases.However, when the above-mentioned mouthpiece 177 is used, the rawmaterial is supplied from not smaller than two kinds of extrusionmolding machines 111 separately and independently to the holes H of theregion 177 a and slit 177 b, so that a suitable wavy form is obtained.Instead of the slit 177 b, holes H may be provided. In such a case, itis recommended that the density of the holes H be set high.

Besides these mouthpieces, mouthpieces of various other specificationscan be used in practice. The density of the holes H formed in theabove-described mouthpieces is preferably set to 1 to 5/cm².

The method of manufacturing a three-dimensional netted structure 1 isutilized.

According to the three-dimensional netted structures 101 to 107, a resindifficult to be separated or a resin impossible to be separated is usedto form the first region 101 a, while a resin possible to be separatedis used to form the second region 101 b, this resin being separatedduring a recycling operation, so that the recycling operation can becarried out repeatedly.

A three-dimensional netted structure divided into regions in accordancewith the properties of the thermoplastic resins can be manufactured, andthe recycling of the thermoplastic resins can be done smoothly. A simpleoperation, such as a region separating operation or some other similaroperation advantageously makes it possible to change the shape of thenetted structure afterward. Since a raw material is supplied to themouthpiece from a plurality of extruders separately and independently,the moldability of the material for the three-dimensional structure isimproved.

An apparatus 210 for manufacturing three-dimensional netted structureaims at providing a method of and an apparatus for manufacturing athree-dimensional netted structure, capable of preventing thedeformation of the endless belts, which causes inconveniences, omittinga finishing operation on a later stage, improving the degree ofstraightness of the surfaces of a netted structure, meeting a demand fora netted structure of modified shapes, and manufacturing a nettedstructure of an improved durability.

The construction of the parts of the apparatus for manufacturing thethree-dimensional netted structure 210 which are different from thecorresponding parts of the apparatuses of other embodiments will bedescribed by utilizing the description of apparatus 10, etc.

The apparatus 210 is formed of an extrusion molding machine 211, a pairof rolls 212, 213 provided in horizontal positions spaced from eachother by a predetermined distance, a pair of rolls 214, 215 (refer toFIG. 20 and FIG. 21) provided below and in alignment with the two rolls212, 213 horizontally so as to be spaced from each other by apredetermined distance, a motor for driving the rolls 212 to 215, atransmission formed of chains and gears and adapted to change the movingspeed of the rolls 212 to 215, a water tank for partly submerging of thetwo rolls 212, 213 and completely submerging the two rolls 214, 215, acontrol unit, meters, etc. Referring to FIG. 20, a structure providedwith three rolls by removing one of the lower rolls may be employed.

The rolls 212, 213 may be formed of cross-section circular rolls 224(refer to FIG. 22( a)) as well as rolls of modified shapes. Variousmodified modes of rolls are conceivable which include, for example, aroll 225 (refer to FIG. 22( b)) having a cross-section saw-tooth outercircumference, a roll having continuously formed recesses andprojections, for example, a roll 226 (refer to FIG. 22( c)) having anouter circumferential surface similar to that of a gear in section, aroll 227 (refer to FIG. 22( d)) having not smaller than one projection227 a (for example, a triangular or circular projection) on an outercircumferential surface thereof, a cross-section elliptic roll 228(refer to FIG. 22( e)), a cross-section triangular or a hand-made ormechanically molded rice-shaped roll 229 (refer to FIG. 22( f)), across-section polygonal roll, for example, a cross-section octagonalroll 230 (refer to FIG. 22( g)), etc.

As shown in FIG. 21, the rolls 212 to 215 are provided with drivingshafts 212 a to 215 a respectively. The driving shafts 212 a to 215 aare supported rotatably on the respective bearings, and driven in thedirections of arrows in FIG. 20 by a driving motor via the transmission.

According to the apparatus 210 described above for manufacturing athree-dimensional netted structure, it becomes possible to omit afinishing operation carried out in a later stage, heighten the degree ofstraightness of surfaces of a netted structure, meet a demand forobtaining netted structures of modified shapes and improve thedurability of a netted structure.

A three-dimensional netted structure 401 is a netted structure in whichsparse portions and dense portions are provided. This netted structurecan be applied to, for example, a wall material from which a gardeningcontainer is suspended, a deck on which a gardening container is placed,a blind, a screen, a bamboo blind-like article, a fence, and a gardeningcushioning material applied to a floral decoration and the like.

The sparse and dense portions of the three-dimensional netted structure401 are formed through an operation for regulating a transfer speed ofthe draw-down unit, for example, endless conveyors or rollers, bycontrolling the rotational speed of the motor. This method enables anetted structure having sparse and dense portions stabler than those ofa netted structure manufactured by regulating the liquid pressure of theextrusion molding machine to be obtained.

As shown in FIG. 23( a), low-density portions 401 a and high-densityportions 401 b are formed in order and in repetition. In addition, asshown in FIG. 23( b), hollow portions 406A, 406B are provided through anetted structure so as to extend in a predetermined direction. Amodified mode of this netted structure may be a gardening cushioningmaterial 402 having a plurality of small through holes 407 a to 407 dextending therethrough in the lengthwise direction as shown in FIG. 23(d). The ranges of the density of the sparse portions 401 a and denseportions 401 b can be set suitably. The raw material of thethermoplastic resin, etc. will be described by utilizing the descriptionembodiments described above.

In order to make hollow portions in the netted structure, regions 477 a,477 b not provided with the holes H are formed in the correspondingparts of the mouthpiece 471 as shown in FIG. 24, and downwardlyextending cross-section square introduction members (plate members,pipes, etc.) 477 c, 477 d are provided (refer to FIG. 24( b)) on lowerportions of these regions. There is another example of the mouthpiecewhich is formed of a mouthpiece 481 (the area of the region thereofwhich is provided with the holes H accounts for 90% of a total area ofthe mouthpiece) (refer to FIG. 24( c)) in which a predetermined numberof holes H are formed at substantially regular intervals. In order toform hollow portions in the netted structure, this mouthpiece isprovided with regions 487 a to 487 d not provided with the holes H inthe corresponding parts thereof, and downwardly extending cross-sectionsquare introduction members (plate members, pipes, etc.) 488 a to 488 dare provided (refer to FIG. 24( d)) on lower portions of the mentionedregions. The density of the holes H formed in the mouthpiece ispreferably 1 to 5/cm². Besides these mouthpieces, mouthpieces of variousspecifications can be used in practice.

The three-dimensional netted structure 401 can be used as substitutesfor a wall member from which a gardening container is suspended, a wallmember for a floral decoration, a blind and a fence. For example, asshown in FIG. 25, piles 480 (posts may be used instead) are driven intothe ground and set up, and the resultant piles are thrust into thehollow portions 406A, 406B of the three-dimensional netted structure 401and fixed. The three-dimensional netted structure 401 may be dividedinto a plurality of parts, and dimensional selectivity thereof may besecured by combining the divided netted structures with each other. Asuitable number of hanging baskets 482 provided with hooks 481 are hungon the sparse portions 401 a. The hooks 481 are hung on sparse portions401 a more easily than on dense portions 401 b.

This netted structure can also be utilized as a deck. For example, athree-dimensional netted structure 490 is not provided with hollowportions but it is manufactured in a step similar to the step ofmanufacturing the three-dimensional netted structure 401, so that aculture pot 491, a container 492 and the like can be placed thereon. Thenetted structure 490 can also be applied to a screen, a bambooblind-like article, a fence, a floral decoration, etc. As shown in FIG.26, a three-dimensional netted structure 402 can be utilized as a roof,a screen, and a partition for plants in a median strip of a road. Thenetted structure 402 is formed so that it can be fixed to a structure bya suitable device or by passing connecting members 403, such as strings,rings, pipes and the like through small holes 407 a to 407 c thereof.When this netted structure is utilized as a partition for the plants ina median strip of a road, a glare-proofing effect is displayed withrespect to the light of an automobile.

According to the three-dimensional netted structure 401 described above,it can be applied to a wall member for hanging baskets, a deck, a blind,etc. Moreover, this netted structure reduces the manufacturing cost, andhas durability with respect to the wind and rain and sunlight. Thenetted structure is not rotted, and the flexure thereof does not occur.The netted structure is rarely discolored. This netted structure canemploy various colors, and the coloring of the netted structure can bedone freely, so that the range of the selection of colors expands.Moreover, the netted structure has a very high resiliency, and enables ablinding effect to increase and an outer appearance of different senseof quality to be provided, so that the netted structure is veryconvenient.

The three-dimensional netted structure can also be used as a seedbed forplanting a roof with trees. The netted structure is laid in a hole or arecess formed in a suitable position on a gas-permeable and awater-permeable tile. The culture earth is put in the hole or recess,and tree is planted therein.

The three-dimensional netted structure can also be used as a pavementmaterial by pasting gas-permeable and water-permeable tiles on an uppersurface thereof. Owing to the netted structure, the temperature can bereduced.

A three-dimensional netted structure can also be manufactured thecharacteristics of which reside in that the netted structure is formedby preparing as a raw material or a main raw material a thermoplasticresin containing a brittleness causing element, such as an inorganicsubstance, for example, talc; forming a plurality of helically andrandomly entangled and partly and thermally bonded filaments of the rawmaterial by extrusion molding; and cooling these filaments with aliquid, the brittle fracture of the product becoming able to be effectedby applying an external force thereto.

A three-dimensional netted structure obtained by preparing athermoplastic resin as a raw material or a main raw material; forming aplurality of helically and randomly entangled and partly and thermallybonded filaments of the raw material by extrusion molding; cooling thesefilaments with a liquid, and applying a fire resistant material to theresultant filaments or enclosing the filaments with a nonwoven carbonfiber, or a similar three-dimensional netted structure made of the samethermoplastic resin to which the fire resistant material is added canalso be manufactured. The three-dimensional netted structure enclosedwith a nonwoven cloth of carbon fiber can be provided in the ceiling andwalls.

A three-dimensional netted structure 510 is manufactured by forming athree-dimensional netted structure 501 by using curved plates 582, 583as shown in FIG. 27, instead of using the endless members and rolls. Thecurved plates 582, 583 extend perpendicularly to the surface of thedrawing, and are given at their outer surfaces a slidability by coatingthe same with polytetrafluoroethylene. The curved plates are rectangularin side elevation. The curved plates 582, 583 are arranged so that adistance therebetween decreases from upper portions thereof toward lowerportions thereof. The curved plates 582, 583 may have a fixed structure,or they may be formed so that the density and shape thereof in thelateral and longitudinal directions can be varied by rendering adistance of the curved plates variable as shown by broken lines byreciprocating driving units 590, 591 (for example, fluid pressurecylinders). A curved plate 584 is also provided below the curved plates582, 583, and introduces the netted structure 501 suitably to adownstream side draw-down unit.

Apparatus and Method for Manufacturing a Three-Dimensional NettedStructure Water-Submerged or Partly-Submerged Drawing-Down Units I

An apparatus 601 for manufacturing a three-dimensional netted structurein other exemplary embodiment is explained below referring to FIG. 28 toFIG. 29. Reference numbers in the exemplary embodiment are in the 600scorresponding to reference numbers of members in the first exemplaryembodiment.

An iron chute, a stainless steel chute and a chute the surface of whichis coated by a layer made of Teflon® have been developed. The surface ofthe chutes can be coated with oil. The chute can be a shot blasted chutewith a surface roughness of Rz from 1 to 80. A chute with a surface thatwas not polished and was ceramic-coated instead or a metal mesh chutecan be used. The surface of a chute can be provided with a stretchedwater-permeable sheet (for example, a cloth) and water can be providedto the chute and the water-permeable sheet (e.g., by spraying orpouring). Thus, the invention also provides an apparatus and a methodfor manufacturing a three-dimensional netted structure with a smoothsurface.

The amount of water supplied to the chute can be adjusted as isappropriate according to the invention. If too much water is supplied tothe chute the filaments would cool too much, and loops of filamentswould not be bonded to each other adequately. If too little water issupplied, the resin falling from the nozzle may stick to the surface ofthe chute forming an uneven surface of the product, or the filaments maybe stretched too thin. Additionally, the amount of water may be variedaccording to the condition of the pump when using well water. Wateramount may be varied with time even when using tap water. Such variationin water amount may affect surface state and bonding state of theproduct.

The inclination angle of the chute is preferably from 35 to 45 degrees.The chute has longitudinal side chutes located longitudinally, lateralside chutes located laterally and a rectangular hole formed by arrangingthe longitudinal side chutes and the lateral side chutes in arectangular shape. The lateral side chutes have an inclination anglesteeper than that of the longitudinal side chutes. The lateral sidechutes are shorter than the longitudinal side chutes. Usually, it issufficient to supply water on only the longitudinal side chutes,although water may be supplied also on the lateral side chutes.Cross-section of the chutes should not be angled at two points.

Water level R, S as shown in FIG. 28 is preferably higher than the lowerend of the chute or the first angled point of the chute. Water level Sis the minimum level. Water level is ordinary between the levels R andS. Distance between the drawing-down units may be narrower or wider thanthe distance between the lower ends of the longitudinal side chutes. Anexemplary embodiment with the same distance is shown in this figure.Water level R is higher than water level S with the difference of 2-30mm, preferably 3-20 mm, more preferably 5-12 mm.

Water flow of 0.8 L/min per 1 m of chute was determined not to besufficient. Water surface becomes almost even when water flow is 1.0L/min, and becomes even when water flow is 1.3 L/min. Water flow of 4.0L/min it too high, and air accumulates under the water-permeable sheet.Fusion bonding strength (tensile strength) was measured using a sampleof the three-dimensional netted structure having a thickness of 35 mm, awidth of 5 cm, a length of 8 cm and an apparent density of 0.0749 g/cm³.Fusion bonding strength was measured with a spring balance with theupper end and the lower end of the sample being fixed with chucks.Forces applied to the spring balance were measured when the sample wasstretched long by 10 mm (namely, when fusion bonding began to break) andwhen the sample was stretched long by 30 mm.

As shown in FIG. 28, an apparatus 601 for manufacturing athree-dimensional netted structure manufactures a three-dimensionalnetted structure 610 by entangling the filaments 620 of thermoplasticresin into random loops and thermally bonding the contacting parts ofthe filaments. The apparatus 601 for manufacturing a three-dimensionalnetted structure has a mouthpiece 603, a chute 604 located below themouthpiece 603, water supplying outlets 605 located above the chute 604,a drawing-down unit 606 located below the chute 604. Cooling water issupplied on the surface of the chute 604. The cooling water receives thefilaments 620 in a surface part of a filament assembly 621, to formloops in the filaments 620 and make the adjacent filaments 620 contactand be entangled with each other. A surface layer 625 having a higherapparent density and an inner layer 626 having a lower apparent densityis thus formed by the chute 604. Width of the filament assembly 621 isreduced to the width of the three-dimensional netted structure 610 withthe ratio of 6-25%, preferably 3-10%, more preferably 4-7%.

Chute 604 comprises longitudinal side chutes 642 a, 642 b and lateralside chute 643 c, 643 d, and has a rectangular shape in a plan view. Athrough hole 649 is formed at the center.

The drawing-down unit 606 has a pair of drawing-down units 606 a and 606b. The detailed structure thereof has already been explained. Thelongitudinal direction of the drawing-unit 606 is parallel to thelongitudinal direction of the chute. The upper part of the drawing-downunit is situated below the longitudinal side chutes 642 a and 642 b. Thedistance between the longitudinal side chutes 642 a and 642 b is thesame as the distance between the drawing-down units 606 a and 606 b.However, the former may be set to be wider than the latter so that thethickness of the three-dimensional netted structure is further narrowedby the drawing-down unit 606.

As shown in FIG. 28, supplying pipes 651 a and 651 b are provided abovethe longitudinal side chutes 642 a and 642 b. The lateral chutes 643 cand 643 d are located vertically to the longitudinal side chutes 642 a,642 b and forming the lateral direction of the three-dimensional nettedstructure 610 (refer to FIG. 29).

Operation and effects of this exemplary embodiment is explained below.As shown in FIGS. 28 and 29, cooling water supplied from the supplyingpipes 651 a and 651 b to the longitudinal side chutes 642 a and 642 b onthe surface of the longitudinal side chutes 642 a and 642 b and forms acooling water layer thereon, while flowing down the surface of thelongitudinal side chutes 642 a and 642 b. The surface of thelongitudinal side chutes 642 a, 642 b is hydrophilic. This enables thecooling water layer to spread evenly all over the surface of thelongitudinal side chutes 642 a, 642 b, preventing the filaments 620 fromsticking to the chute and preventing poor formation of thethree-dimensional netted structure 610 due to lack of cooling water.Thus, cooling and solidification of the filament assembly 621 andformation of the three-dimensional netted structure 610 proceedsmoothly.

Apparatus and Method for Manufacturing a Three-Dimensional NettedStructure Separated Type Chute

An apparatus 801 for manufacturing a three-dimensional netted structurein the exemplary embodiment is explained below referring to FIG. 30.Reference numbers in the exemplary embodiment are in the 800scorresponding to reference numbers of members in the first exemplaryembodiment.

For example, the three-dimensional netted structure is applied for apillow.

A chute 804 of the apparatus 801 for manufacturing a three-dimensionalnetted structure has separated chutes 847 a, 847 b, 847 c, 847 d andtheir respective separated inclined surfaces 848 a, 848 b, 848 c, 848 d.The separated chutes 847 a, 847 c, 847 d of a curved shape and theseparated chute 847 b of a straight shape are assembled to form acontinuous surface. In this case, cooling water may be also supplied tothe lateral part. However, it is sufficient to supply cooling water tothe longitudinal part, namely the separated chutes 847 b, 847 d and alittle to the left and right from the separated chutes. Water supplyoutlets are not shown in FIG. 30.

Separated type chute 804 has an advantage that three-dimensional nettedstructures of not only rectangular cross-sectional shape but also ofarbitrary cross-sectional shapes can be manufactured by changing a partof the chute 804.

The chute 804 may be made of an integral single plate (not shown).

Usually, a surface layer having a higher apparent density and an innerlayer having a lower apparent density located inside said surface layerare formed by the chute although there is the range of the grade ofhardness. Moreover, the combination with a non-woven fabric and thecombination with urethane sheet, pad, or cloth are made to belong-lasting. When a substance, for example mortar, is put in the coreof the three dimensional netted structure for a shock absorber, thethree dimensional netted structure can be made without a surface layerhaving a higher apparent density by raising the water level above thestandard level or by reducing the number of the filaments of a surfacelayer. Apparent density is changed by varying the speed of the draw-downapparatus.

Apparatus and Method for Manufacturing a Three-Dimensional NettedStructure Water-Submerged or Partly-Submerged Drawing-Down Units II

An apparatus 901 for manufacturing a three-dimensional netted structurein other exemplary embodiment is explained below referring to FIG. 31.Reference numbers in the exemplary embodiment are in the 900scorresponding to reference numbers of members in the first exemplaryembodiment.

The upper end of the drawing-down units 906 may be above or under thewater depending on the condition of the water level as shown in FIGS.31( a) and 31(b). The distance B1 between the drawing-down units 906 isnarrower than the distance S1 between the chutes 742 a, 742 b with a %ratio of B1:S1=99−87:100, preferably 98−90:100.

Apparatus and Method for Manufacturing a Three-Dimensional NettedStructure Water-Submerged or Partly-Submerged Drawing-Down Units III

An apparatus 1001 for manufacturing a three-dimensional netted structurein other exemplary embodiment is explained below referring to FIG. 32.Reference numbers in the exemplary embodiment are in the 1000scorresponding to reference numbers of members in the first exemplaryembodiment. Explanation of the first exemplary embodiment is quotedherein.

There is provided a predetermined interval T between the edge of thefilament assembly 1021 and the boundary that is defined by water lever Rand the chutes 1042 a, 1042 b so that the filament assembly 1021 is setwithin such boundary. The filament assembly 1021 contacts with thechutes 1042 a, 1042 b below water surface. The width of the filamentassembly 1021 can be further narrowed.

Alternatively, hot water may be supplied to cool the filaments in theabove exemplary embodiments.

INDUSTRIAL APPLICABILITY

Methods of and apparatuses for manufacturing a three-dimensional nettedstructure, capable of omitting a finishing operation in a later stage,heightening the degree of straightness of side surfaces of the nettedstructure, meeting a demand for obtaining netted structure of modifiedshapes, and improving the durability of the netted structure can beprovided, and the value of industrial utilization of these inventions invarious kinds of industries is very large.

1. A method of manufacturing a three-dimensional netted structure, themethod comprising: extruding molten filaments of a thermoplastic resindownward from a die via a mouthpiece of the die having a plurality ofholes, whereby the filaments drop under the force of gravity in betweendrawing-down units, said drawing-down units being submerged orpartly-submerged in a liquid, wherein the distance between saiddrawing-down units is smaller than the width of an assembly of saidextruded filaments; drawing down the assembly of extruded filaments at aspeed lower than the filament dropping speed by said drawing-down units,wherein four surfaces of the assembly of said filaments are contactingsaid drawing-down units before or after said drawing-down units aresubmerged; and cooling said resultant filaments with a liquid.
 2. Themethod of claim 1, wherein said mouthpiece has a slit in addition tosaid plurality of holes, the slit extending in the lengthwise directionof the mouthpiece whereby the three-dimensional netted structureadditionally comprises a substantially non-void-carrying sheet whichforms a wavy shape in a direction in which the resin is extruded.
 3. Themethod of claim 1, wherein said mouthpiece has a region not providedwith holes whereby manufacturing a hollow portion in thethree-dimensional netted structure arranged in a direction in which theresin is extruded.
 4. The method of claim 1, wherein the filaments flowalong a liquid layer formed on a chute to form loops in the filaments,and wherein adjacent filaments contact each other, are entangled witheach other, and drop in-between the drawing-down units.